1. Field of the Invention
The present invention relates to a dispenser, and particularly to a technique which is effectively applicable to a dispenser which supplies a predetermined amount of cream solder for bonding a pellet onto a package or a lead frame in technologies of a semiconductor integrated circuit manufacturing device.
2. Prior Art
In a well known dispenser, a plunger is housed movably in an axial direction in a container of a material to be dispensed and shifts toward a nozzle by a predetermined distance to push a predetermined amount of the material so that it is ejected from the nozzle.
In an automatic assembly line using a dispenser of this kind, it is necessary to refill a dispensing material into a container or to exchange a container for new one, by detecting a remaining amount of material in the container before it is used up. In order to detect decrease of the dispensing material, there has been employed a method where decrease in the material is detected visually by an operator, or a method where use-up time is predicted based on a planed amount of the dispensing material.
However, such a production control employing the visual detection by an operator or the time prediction detecting method requires much effort and there is a fear that such unreliable detecting methods may lead to faulty products.